Second-harmonic generation of ZnO nanoparticles synthesized by laser ablation of solids in liquids

We report the synthesis of small zinc oxide nanoparticles (ZnO NPs) based colloidal suspensions and the study of second-harmonic generation from aggregated ZnO NPs deposited on glass substrates. The colloidal suspensions were obtained using the laser ablation of solids in liquids technique, ablating a Zn solid target immersed in acetone as the liquid medium, with ns-laser pulses (1064 nm) of a Nd-YAG laser. The per pulse laser fluence, the laser repetition rate frequency and the ablation time were kept constant. The absorption evolution of the obtained suspensions was optically characterized through absorption spectroscopy until stabilization. Raman spectroscopy, SEM and HRTEM were used to provide evidence of the ZnO NPs structure. HRTEM results showed that 5–8 nm spheroids ZnO NPs were obtained. Strong second-harmonic signal is obtained from random ZnO monocrystalline NPs and from aggregated ZnO NPs, suggesting that the high efficiency of the nonlinear process may not depend on the NPs size or aggregation state

Synthesis of molybdenum oxide nanoparticles by nanosecond laser ablation

Phothermal therapy (PTT) is one of the most promising techniques to treat cancer. Finding the ideal PTT agent nanomaterial has remained a challenge and has brought the interest of several researchers. In this work, we report the synthesis of molybdenum oxide (MoOx) nanoparticles (NPs), which exhibit absorption in the biological optical window ~840 nm, by using the laser ablation of solids in liquids (LASL) technique with nanosecond (ns) pulses. A Nd:YAG laser was used to synthesize the NPs in deionized (DI) water, free of surfactants or additives, which were optically characterized by absorption spectroscopy and TEM-EDX microscopy. Semi spherical NPs with a suitable average size and shape for potential use as PTT agents were obtained by laser ablation and ablation + fragmentation. The calculated band gap is 3.1 eV, which corresponds to MoO3. Micro-Raman spectroscopy studies determined that these NPs are composed of amorphous molybdenum oxide hydrates (MoO3 · xH2O)

Travel patterns to employment in a border city Mexico – USA with geographic information systems : Mexicali

En este escrito se presenta la caracterización de la movilidad urbana del traslado hacia el empleo en una ciudad fronteriza de México con Estados Unidos: Mexicali, Baja California, a partir de una matriz origen-destino de viajes elaborada con información de fuentes oficiales y el uso de sistemas de información geográfica. Con el análisis territorial se realizó el cálculo de indicadores como distancias y tiempos de recorrido, combustible consumido y generación de gases efecto invernadero (GEI), información que puede resultar de utilidad para los tomadores de decisiones en el proceso de planeación urbana y ambiental.This paper presents the characterization of commuting in a border city of Mexico with the United States: Mexicali, Baja California, from an origin-destination matrix of trips which was elaborated with official sources and the use of geographic information systems. With the territorial analysis, other indicators were calculated such as distances and travel times, fuel consumption and generation of greenhouse gases (GHG), information that can be useful for decision-makers in the urban and environment planning process.Fil: Santos-Gómez, Ma. de los Ángeles. Universidad Autónoma de Baja California Sur (México)Fil: Leyva Camacho, Osvaldo. Universidad Autónoma de Baja California Sur (México

Effect of Crystallization Conditions on the Metastable Zone Width and Nucleation Kinetics of p ‐Aminobenzoic Acid in Ethanol

A detailed knowledge of the metastable zone width (MSZW) and nucleation kinetics is vital for the design of batch cooling crystallization processes. Factors such as cooling rate and impeller speed affect the MSZW and nucleation kinetics. Crystallization and dissolution temperatures were measured as a function of cooling rate and impeller speed during the batch cooling crystallization of p ‐aminobenzoic acid (pABA) from ethanol in a 0.5‐L stirred‐tank crystallizer. The polythermal experimental data were analyzed using the Nyvlt and first principles‐based Kashchiev‐Borissova‐Hammond‐Roberts (KBHR) methods. In all experimental cases, the latter model revealed that the nucleation process of pABA in ethanol was dominated by an instantaneous nucleation mechanism. The Nyvlt and KBHR analyses delivered a range of parameter values associated with a power‐law model describing the nucleation rate as well as the concentration of nuclei

Genetic variants of innate immune receptors and infections after liver transplantation.

Infection is the leading cause of complication after liver transplantation, causing morbidity and mortality in the first months after surgery. Allograft rejection is mediated through adaptive immunological responses, and thus immunosuppressive therapy is necessary after transplantation. In this setting, the presence of genetic variants of innate immunity receptors may increase the risk of post-transplant infection, in comparison with patients carrying wild-type alleles. Numerous studies have investigated the role of genetic variants of innate immune receptors and the risk of complication after liver transplantation, but their results are discordant. Toll-like receptors and mannose-binding lectin are arguably the most important studied molecules; however, many other receptors could increase the risk of infection after transplantation. In this article, we review the published studies analyzing the impact of genetic variants in the innate immune system on the development of infectious complications after liver transplantation

Somatotype and Digital Dermatoglyph in Mexican Football Players

La valoración de la forma corporal y de las capacidades físicas es una necesidad para la selección, clasificación y entrenamiento de los jugadores de futbol. El presente estudio examinó en futbolistas profesionales mexicanos (N = 49) la relación entre clases de somatotipo y clases de capacidades físicas de acuerdo a dermatoglifia dactilar. Las frecuencias de clases de somatotipo y clases de capacidad física fueron comparadas entre subgrupos de futbolistas. Una mayor proporción de futbolistas se caracterizó por somatotipo mesomorfo balanceado con dermatoglifia tipo 2 y 3 correspondiente a fuerza, fuerza explosiva y velocidad. Esto es consistente con hallazgos previos en futbolista

Morphological population balance modelling of the effect of crystallisation environment on the evolution of crystal size and shape of para-aminobenzoic acid

A current morphological population balance (MPB) modelling methodology, which integrates crystal morphology, facet growth kinetics with multi-dimensional population balance, is overviewed and demonstrated, hence providing an attractive approach for modelling crystallisation processes. MPB modelling is applied to simulate the batch crystallisation of the alpha-form of para-aminobenzoic acid from ethanolic solutions as a function of the crystallisation environment including cooling rate, seeding temperature and seed conditions (loading, size and shape). The evolution of crystal shape/size and their distributions revealed that higher loading led to smaller and less needle-like crystals with similar yields, hence potentially being an important parameter for process control. Examination of the development of the fracture surface for broken seeds, mimicking the seed conditions after milling in practice in the simulated processes, demonstrated that these faces grew fast and then rapidly disappeared from the external crystal morphology. Restriction and challenges inherent in the current model are also highlighted

Factores Asociados a Hemorragia Intraventricular En Neonatos Atendidos En Un Hospital de Segundo Nivel

Intraventricular hemorrhage (HIV) is a complication in neonates. It originates in the subependymal germinal matrix. This area is irrigated by a network of poorly differentiated vessels without a basement membrane. Also, it is fragile and vulnerable to the hemodynamic instability of cerebral blood flow. It is an important risk factor for periventricular leukomalacia, ventriculomegaly, and hydrocephalus. These neurological pathologies can generate sequelae in the pediatric population such as cerebral palsy (CP). Objective: To identify the factors associated with HIV in neonates treated in the early intervention program of the hospital of specialties of the child and the woman of the Secretary of Health of the State of Querétaro (HENMSESEQ). Material and Methods: Through the review of the clinical files, the factors associated with HIV present in the children attended to in the HENMSESEQ early intervention service were observed in 2015. Cases of HIV were corroborated by means of transfontanel ultrasound, statistical analysis with measures of central tendency, and comparison of the medians of children diagnosed with HIV and without diagnosis. Results: A group of 69 infants attended to in the early intervention program was studied. Out of them, 65.2% (45) were women and 34.3% (24) were men. They had a gestational age of 34.19 ± 4.22 weeks, birth weight of 2116.09 ± 859.36 g, and height of 44.06 ± 6.02 cm. Their stay in the Neonatal Intensive Care Unit (NICU) for the sample was 11.88 ± 16.84 days and they were 8.65 ± 12.20 days with invasive mechanical ventilation. There were 25 cases of HIV diagnosed by  transfontanel ultrasound. Out of the 25 cases, 7 (10%) were HIV grade I, 14 (20%) II, 4 (5.7%) III, and no cases of grade IV were diagnosed. Using the Mann-Whitney U test, a difference was found between the groups of neonates diagnosed with HIV and without diagnosis in weeks of gestation, height, weight, APGAR, days of intubation, and days of stay in NICU

Photon Gas Thermodynamics in Doubly Special Relativity

Doubly special relativity (DSR), with both an invariant velocity and an invariant length scale, elegantly preserves the principle of relativity between moving observers, and appears as a promising candidate of the quantum theory of gravity. We study the modifications of photon gas thermodynamics in the framework of DSR with an invariant length $|\lambda|$, after properly taking into account the effects of modified dispersion relation, upper bounded energy-momentum space, and deformed integration measure. We show that with a positive $\lambda$, the grand partition function, the energy density, the specific heat, the entropy, and the pressure are smaller than those of special relativity (SR), while the velocity of photons and the ratio of pressure to energy are larger. In contrast, with a negative $\lambda$, the quantum gravity effects show up in the opposite direction. However, these effects only manifest themselves significantly when the temperature is larger than $10^{-3} E_{\rm P}$. Thus, DSR can have considerable influence on the early universe in cosmological study.Comment: 17 pages, 7 figures, final version for publication in AP

Mechanical Stimulation of Cells Through Scaffold Design for Tissue Engineering

Tissue engineering scaffolds attempt to mimic the stem cell environment by creating different biophysical and chemical signals. On the other hand, stem cells are able to sense these characteristics and change their destiny. Scientists try to explain these phenomena through scaffold design and in vitro experiments, but the mechanisms implicated remain unclear. Moreover, environment-cell interactions are a key process to get organs and tissues arrangement. Therefore, this chapter deals with the mechanical signals and mechanism involved in cell behaviour through scaffolds as a strategy in tissue engineering